U.S. patent number 6,283,233 [Application Number 09/319,491] was granted by the patent office on 2001-09-04 for drilling and/or coring tool.
This patent grant is currently assigned to Dresser Industries, Inc. Invention is credited to Sebastian Desmette, Cecile Josse, Etienne Lamine.
United States Patent |
6,283,233 |
Lamine , et al. |
September 4, 2001 |
**Please see images for:
( Certificate of Correction ) ** |
Drilling and/or coring tool
Abstract
A drill and/or core tool, in particular for oil drilling and/or
coring, comprising a body (2) showing a substantially cylindrical
peripheral surface (3) and a front (4), blades (5) which extend
from the front (4) till over the peripheral surface (3) and which
show each a leading edge (6), possibly PDC cutting elements (7)
which are situated at least in a central area (15A) of the front
(4) and the longitudinal axes of which are transverse to the
rotation axis of the tool (1), and comprising moreover, on at least
one blade (5), outside said central area (15A): PDC (7C) and/or
secondary (10) cutting elements which show each a cutting edge (8),
forming together the leading edge (6) of the blade (5), and the
longitudinal axis of which is transverse to the rotation axis, and
at least one associated cutting element (10A) which is situated
behind at least one of the PDC (7C) or secondary (10) cutting
elements, which shows a cross-section of the same shape, at least
for its portion protruding from the blade (5), than that of the PDC
(7C) or secondary (10) cutting element, and which is disposed on
the same blade (5).
Inventors: |
Lamine; Etienne
(Court-Saint-Etienne, BE), Desmette; Sebastian
(Soignies, BE), Josse; Cecile (Hoves, BE) |
Assignee: |
Dresser Industries, Inc
(Carrollton, TX)
|
Family
ID: |
3890144 |
Appl.
No.: |
09/319,491 |
Filed: |
July 19, 1999 |
PCT
Filed: |
December 16, 1997 |
PCT No.: |
PCT/BE97/00136 |
371
Date: |
July 19, 1999 |
102(e)
Date: |
July 19, 1999 |
PCT
Pub. No.: |
WO98/27311 |
PCT
Pub. Date: |
June 25, 1998 |
Foreign Application Priority Data
|
|
|
|
|
Dec 16, 1996 [BE] |
|
|
09601042 |
|
Current U.S.
Class: |
175/431;
175/405.1 |
Current CPC
Class: |
E21B
10/006 (20130101); E21B 10/55 (20130101); E21B
10/48 (20130101); E21B 10/43 (20130101) |
Current International
Class: |
E21B
10/54 (20060101); E21B 10/00 (20060101); E21B
10/46 (20060101); E21B 10/48 (20060101); E21B
10/42 (20060101); E21B 010/46 (); E21B
010/48 () |
Field of
Search: |
;15/431,430,428,405.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1218567 |
|
May 1960 |
|
FR |
|
2620487 |
|
Mar 1989 |
|
FR |
|
2204625A |
|
Nov 1988 |
|
GB |
|
Primary Examiner: Dang; Hoang
Attorney, Agent or Firm: Browning Bushman P.C.
Claims
What is claimed is:
1. A drill or core tool for oil drilling or coring, comprising:
a body (2) showing a substantially cylindrical peripheral surface
(3) and a front (4), considered in a movement direction during
drilling or coring,
blades (5) which extend from the front (4) till over the peripheral
surface (3) and which show each leading edge (6) for the drilling
or coring,
PDC cutting elements (7) which are situated at least in a central
area (15A) of the front (4) and the longitudinal axis of which are
transverse to the rotation axis of the tool(1), and
nozzles (9) for supplying a drilling liquid,
characterized in that it comprises moreover, on at least one blade
(5), outside said central area (15A),
PDC cutting elements (7C) and/or secondary cutting elements (10)
which show each a cutting edge (8), forming together the leading
edge (6) of the blade (5), and the longitudinal axis of which is
transverse to the rotation axis, and
at least one associated cutting element (10A)
which is situated, when considering a drilling rotation (S) of the
tool (1), behind at least one of the PDC (7C) or secondary (10)
cutting elements,
which shows a cross-section of the same shape, at least for its
portion protruding from the blade (5), as that of the PDC (7C) or
secondary (10) cutting element,
which is disposed on the same blade (5),
an edge (11) of which destined for cutting is situated at the most
on a same radial distance (R) from the rotation axis and at least
on a same distance (D), measured parallel to this rotation axis
starting from a plane (P) perpendicular to this axis and situated
in front of the tool (1), as that of the cutting edge (8) of said
PDC (7C) or secondary (10) element, and
further characterized in that the associated cutting element (10A)
is practically coupled by an end face to the adjacent end face of
the PDC (7C) or secondary (10) or associated (10A) cutting element
which is situated immediately next thereto on the same blade (5)
and substantially on the same of said distances (D, R).
2. A tool as defined in claim 1 characterized in that the secondary
(10) and/or associated (10A) cutting elements are elements which
are prefabricated by sintering and which comprise abrasive grits
and a metallic bond.
3. A tool as defined in claim 1 further characterized in that the
leading edge (6) of the blades (5) has the shape of a helix with a
variable radius and which turns, at least along said peripheral
surface (3), either in the direction opposite to the drilling
rotation (S) or in the same direction as it moves away from the
front (4).
4. A tool as defined in claim 2 further characterized in that the
leading edge (6) of the blades (5) has the shape of a helix with a
variable radius and which turns, at least along said peripheral
surface (3), either in the direction opposite to the drilling
rotation (S) or in the same direction as it moves away from the
front (4).
5. A tool as defined in claim 1 further characterized in that the
width of a blade (5), taken in a projection plane perpendicular to
the rotation axis, increases as one moves away from this rotation
axis over the front (4), and/or from this front in the direction of
a back (15) of the tool (1).
6. A tool as defined in claim 2 further characterized in that the
width of a blade (5), taken in a projection plane perpendicular to
the rotation axis, increases as one moves away from this rotation
axis over the front (4), and/or from this front in the direction of
a back (15) of the tool (1).
7. A tool as defined in claim 1 further characterized in that
secondary (10) and/or associated (10A) cutting element are made of
a composite material containing abrasive particles.
8. A tool as defined in claim 2 further characterized in that
secondary (10) and/or associated (10A) cutting element are made of
a composite material containing abrasive particles.
9. A tool as defined in claim 1 further characterized in that
secondary (10) and/or associated (10A) elements are thermally
stable synthetic diamonds.
10. A tool as defined in claim 2 further characterized in that
secondary (10) and/or associated (10A) elements are thermally
stable synthetic diamonds.
11. A tool as defined in claim 1 further characterized in that the
nozzles (9) are composed of prefabricated elements placed in
locations provided in a production mould, at the same time as the
PDC (7) and/or secondary (10) and associated (10A) cutting elements
are placed therein in adequate locations, the mould being
subsequently filled with solid elements and powdery materials which
form, after infiltration of liquid metal, the body (2) and the
actual blades (5).
12. A tool as defined in claim 2 further characterized in that the
nozzles (9) are composed of prefabricated elements placed in
locations provided in a production mould, at the same time as the
PDC (7) and/or secondary (10) and associated (10A) cutting elements
are placed therein in adequate locations, the mould being
subsequently filled with solid elements and powdery materials which
form, after infiltration of liquid metal, the body (2) and the
actual blades (5).
13. A tool as defined in claim 1 further characterized in that at
least one blade (5) extends in the central area (15A) of the front
(4) and comprises at least one of the PDC cutting elements (7)
arranged for acting in the middle of this front (4), the cutting
edge (8) of this PDC cutting element (7) pertaining to the leading
edge (6) of said blade (5).
14. A tool as defined in claim 2 further characterized in that at
least one blade (5) extends in the central area (15A) of the front
(4) and comprises at least one of the PDC cutting elements (7)
arranged for acting in the middle of this front (4), the cutting
edge (8) of this PDC cutting element (7) pertaining to the leading
edge (6) of said blade (5).
15. A tool as defined in claim 1 further characterized in that, in
the central area (15A), the front (4) is concave and in that the
cutting elements (7, 10, 10A) are disposed therein to cut out a
drill hole bottom of a substantially conical shape with a low
gradient with respect to a plane perpendicular to the rotation
axis.
16. A tool as defined in claim 2 further characterized in that, in
the central area (15A), the front (4) is concave and in that the
cutting elements (7, 10, 10A) are disposed therein to cut out a
drill hole bottom of a substantially conical shape with a low
gradient with respect to a plane perpendicular to the rotation
axis.
17. A tool as defined in claim 1 further characterized in that at
least one associated cutting element (10) has an oblong
cross-section and in that the largest dimension of this
cross-section is preferably directed substantially perpendicularly
to a plane tangential to an envelope (15B) of the cutting elements
(7, 10, 10A) at the place of contact between the cutting edge (11)
of the concerned associated element (10A) and said envelope
(15B).
18. A tool as defined in claim 2 further characterized in that at
least one associated cutting element (10) has an oblong
cross-section and in that the largest dimension of this
cross-section is preferably directed substantially perpendicularly
to a plane tangential to an envelope (15B) of the cutting elements
(7, 10, 10A) at the place of contact between the cutting edge (11)
of the concerned associated element (10A) and said envelope
(15B).
19. A tool as defined in claim 1 further characterized in that the
longitudinal axis of at least certain of the PDC (7) and/or
secondary (10) cutting elements show an inclination with respect to
a plane perpendicular to the rotation axis in such a manner that
their end face comprising the cutting edge (8) is turned somewhat
to a bottom of the hole to be drilled.
20. A tool as defined in claim 2 further characterized in that the
longitudinal axis of at least certain of the PDC (7) and/or
secondary (10) cutting elements show an inclination with respect to
a plane perpendicular to the rotation axis in such a manner that
their end face comprising the cutting edge (8) is turned somewhat
to a bottom of the hole to be drilled.
21. A tool as defined in claim 1 further characterized in that the
longitudinal axis of at least certain secondary (10) and/or
associated (10A) elements is comprised each time in a plane
perpendicular to the rotation axis.
22. A tool as defined in claim 2 further characterized in that the
longitudinal axis of at least certain secondary (10) and/or
associated (10A) elements is comprised each time in a plane
perpendicular to the rotation axis.
23. A drill or core tool for oil drilling or coring,
comprising:
a body (2) showing a substantially cylindrical peripheral surface
(3) and a front (4), considered in a movement direction during
drilling or coring,
blades (5) which extend from the front (4) till over the peripheral
surface (3) and which show each leading edge (6) for the drilling
or coring,
PDC cutting elements (7) which are situated at least in a central
area (15A) of the front (4) and the longitudinal axis of which are
transverse to the rotation axis of the tool (1), and
nozzles (9) for supplying a drilling liquid,
characterized in that it comprises moreover, on at least one blade
(5), outside said central area (15A),
PDC cutting elements (7C) and/or secondary cutting elements (10)
which show each a cutting edge (8), forming together the leading
edge (6) of the blade (5), and the longitudinal axis of which is
transverse to the rotation axis, and
at least one associated cutting element (10A)
which is situated, when considering a drilling rotation (S) of the
tool (1), behind at least one of the PDC (7C) or secondary (10)
cutting elements,
which shows a cross-section of the same shape, at least for its
portion protruding from the blade (5), as that of the PDC (7C) or
secondary (10) cutting element,
which is disposed on the same blade (5),
an edge (11) of which destined for cutting is situated at the most
on a same radial distance (R) from the rotation axis and at least
on a same distance (D), measured parallel to this rotation axis
starting from a plane (P) perpendicular to this axis and situated
in front of the tool (1), as that of the cutting edge (8) of said
PDC (7C) or secondary (10) element, and
characterized further in that the width of a blade (5), taken in a
projection plane perpendicular to the rotation axis, increases as
one moves away from this rotation axis over the front (4), and/or
from this front in the direction of a back (15) of the tool (1),
and
characterized further in that the number of associated cutting
element (10A) arranged one behind the other on a same blade (5) and
on the same of said distances (D, R) radial and parallel to the
rotation axis, increases progressively with one associated cutting
element (10A) having a length equal to the length of said secondary
cutting elements (10), as the width of the blade (5) increases.
24. A tool as defined in claim 23 characterized in that the
secondary (10) and/or associated (10A) cutting elements are
elements which are prefabricated by sintering and which comprise
abrasive grits and a metallic bond.
25. A tool as defined in claim 23 further characterized in that
secondary (10) and/or associated (10A) cutting element are made of
a composite material containing abrasive particles.
26. A tool as defined in claim 24 further characterized in that
secondary (10) and/or associated (10A) cutting element are made of
a composite material containing abrasive particles.
27. A tool as defined in claim 23 further characterized in that
secondary (10) and/or associated (10A) elements are thermally
stable synthetic diamonds.
28. A tool as defined in claim 24 further characterized in that
secondary (10) and/or associated (10A) elements are thermally
stable synthetic diamonds.
29. A tool as defined in claim 23 further characterized in that the
nozzles (9) are composed of prefabricated elements placed in
locations provided in a production mould, at the same time as the
PDC (7) and/or secondary (10) and associated (10A) cutting elements
are placed therein in adequate locations, the mould being
subsequently filled with solid elements and powdery materials which
form, after infiltration of liquid metal, the body (2) and the
actual blades (5).
30. A tool as defined in claim 24 further characterized in that the
nozzles (9) are composed of prefabricated elements placed in
locations provided in a production mould, at the same time as the
PDC (7) and/or secondary (10) and associated (10A) cutting elements
are placed therein in adequate locations, the mould being
subsequently filled with solid elements and powdery materials which
form, after infiltration of liquid metal, the body (2) and the
actual blades (5).
31. A tool as defined in claim 23 further characterized in that at
least one blade (5) extends in the central area (15A) of the front
(4) and comprises at least one of the PDC cutting elements (7)
arranged for acting in the middle of this front (4), the cutting
edge (8) of this PDC cutting element (7) pertaining to the leading
edge (6) of said blade (5).
32. A tool as defined in claim 24 further characterized in that at
least one blade (5) extends in the central area (15A) of the front
(4) and comprises at least one of the PDC cutting elements (7)
arranged for acting in the middle of this front (4), the cutting
edge (8) of this PDC cutting element (7) pertaining to the leading
edge (6) of said blade (5).
33. A tool as defined in claim 23 further characterized in that, in
the central area (15A), the front (4) is concave and in that the
cutting elements (7, 10, 10A) are disposed therein to cut out a
drill hole bottom of a substantially conical shape with a low
gradient with respect to a plane perpendicular to the rotation
axis.
34. A tool as defined in claim 24 further characterized in that, in
the central area (15A), the front (4) is concave and in that the
cutting elements (7, 10, 10A) are disposed therein to cut out a
drill hole bottom of a substantially conical shape with a low
gradient with respect to a plane perpendicular to the rotation
axis.
35. A tool as defined in claim 23 further characterized in that at
least one associated cutting element (10) has an oblong
cross-section and in that the largest dimension of this
cross-section is preferably directed substantially perpendicularly
to a plane tangential to an envelope (15B) of the cutting elements
(7, 10, 10A) at the place of contact between the cutting edge (11)
of the concerned associated element (10A) and said envelope
(15B).
36. A tool as defined in claim 24 further characterized in that at
least one associated cutting element (10) has an oblong
cross-section and in that the largest dimension of this
cross-section is preferably directed substantially perpendicularly
to a plane tangential to an envelope (15B) of the cutting elements
(7, 10, 10A) at the place of contact between the cutting edge (11)
of the concerned associated element (10A) and said envelope
(15B).
37. A tool as defined in claim 23 further characterized in that the
longitudinal axis of at least certain of the PDC (7) and/or
secondary (10) cutting elements show an inclination with respect to
a plane perpendicular to the rotation axis in such a manner that
their end face comprising the cutting edge (8) is turned somewhat
to a bottom of the hole to be drilled.
38. A tool as defined in claim 24 further characterized in that the
longitudinal axis of at least certain of the PDC((7) and/or
secondary (10) cufting elements show an inclination with respect to
a plane perpendicular to the rotation axis in such a manner that
their end face comprising the cutting edge (8) is turned somewhat
to a bottom of the hole to be drilled.
39. A tool as defined in claim 23 further characterized in that the
longitudinal axis of at least certain secondary (10) and/or
associated (10A) elements is comprised each time in a plane
perpendicular to the rotation axis.
40. A tool as defined in claim 24 further characterized in that the
longitudinal axis of at least certain secondary (10) and/or
associated (10A) elements is comprised each time in a plane
perpendicular to the rotation axis.
41. A drill or core tool for oil drilling or coring,
comprising:
a body (2) showing a substantially cylindrical peripheral surface
(3) and a front (4), considered in a movement direction during
drilling or coring,
blades (5) which extend from the front (4) till over the peripheral
surface (3) and which show each leading edge (6) for the drilling
or coring,
PDC cutting elements (7) which are situated at least in a central
area (15A) of the front (4) and the longitudinal axis of which are
transverse to the rotation axis of the tool(1), and
nozzles (9) for supplying a drilling liquid,
characterized in that it comprises moreover, on at least one blade
(5), outside said central area (15A),
PDC cutting elements (7C) and/or secondary cutting elements (10)
which show each a cutting edge (8), forming together the leading
edge (6) of the blade (5), and the longitudinal axis of which is
transverse to the rotation axis, and
at least one associated cutting element (10A)
which is situated, when considering a drilling rotation (S) of the
tool (1), behind at least one of the PDC (7C) or secondary (10)
cutting elements,
which shows a cross-section of the same shape, at least for its
portion protruding from the blade (5), as that of the PDs (7C) or
secondary (10) cutting element,
which is disposed on the same blade (5),
an edge (11) of which destined for cutting is situated at the most
on a same radial distance (R) from the rotation axis and at least
on a same distance (D), measured parallel to this rotation axis
starting from a plane (P) perpendicular to this axis and situated
in front of the tool (1), as that of the cutting edge (8) of said
PDC (7C) or secondary (10) element,
further characterized in that the PDC cutting elements (7) and/or
the secondary (10) and/ or associated (10A) cutting elements are
cylindrical and have equal diameters, and further characterized in
that the associated cutting element (10A) is practically coupled by
an end face to the adjacent end face of the PDC (7C) or secondary
(10) or associated (10A) cutting element which is situated
immediately next thereto on the same blade (5) and substantially on
the same of said distances (D, R).
42. A tool as defined in claim 41 further characterized in that the
secondary (10) and/or associated (10A) cutting elements are
elements which are prefabricated by sintering and which comprise
abrasive grits and a metallic bond.
43. A bit for cutting into a formation comprising:
an axially extending bit body adapted to be rotated in a forward
cutting motion to cut into a formation, said bit body having a
substantally cylindrical peripheral surface with a forward drilling
face at a front axial end and a rearward connection area at a rear
axial end,
blades extending substantially radially along the forward drilling
face and substantially axially along the peripheral surface of said
body,
a leading edge on the blades, said edge leading relative to the
direction of forward cutting motion of the bit body,
leading cutting elements situated along the leading edge of the
blades, said leading cutting elements adapted to cut a path through
the formation as the bit body is rotated in a forward motion,
associated cutting elements situated behind leading cutting
elements on the same blades, the associated cutting elements having
a central cutter axis with a mounting section adapted to be
received within a bit blade for securing the associated cutting
element to the blade and a cutting section extending away from the
blade for cutting the formation, the associated cutting elements
being associated with a leading cutting element,
said mounting section and said cutting section of each said
associated cutting element having the same physical construction
and composition, and
said associated cutting element being disposed on the blade with
its central cutter axis extending substantially in the direction of
rotating motion of the bit body with at least a portion of the
cutting section disposed to trail in the groove cut by the
associated leading cutter element.
44. A bit as defined in claim 43 wherein a portion of each
associated cutting element is buried in the blade to secure the
associated cutting element to the bit body and wherein the
associated cutting element thus secured has a substantially uniform
thickness and a cross section, taken along a plane disposed at a
right angle to said central cutter axis, that is substantially
circular, oblong, elliptic or oval with a portion of a
correspondingly shaped cutting face at least partially presented to
the formation in the direction of bit rotation.
45. A bit as defined in claim 43 wherein the leading cutting
elements comprise polycrystalline diamond compacts (PDC) cutting
elements and the associated cutting elements are comprised of a
composite material containing abrasive particles.
46. A bit as defined in claim 43 wherein the blades increase in
width in a direction from said forward drilling face toward said
rearward connection area.
47. A bit as defined in claim 43 wherein multiple associated
cutting elements are associated with each other and a leading
cutting element on the same blade and at least a portion of each
multiple associated cutting element is disposed to trail in the
groove cut by one of the cutting elements with which it is
associated.
48. A bit as defined in claim 47 wherein the blades increase in
width in a direction from said forward drilling face toward the
rearward connection area.
49. A bit as defined in claim 48 wherein the number of associated
cutting elements associated with a leading cutting element on the
same blade increases as the width of the blade increases.
50. A bit as defined in claim 47 wherein said blades have a
variable width and an increasing number of multiple associated
cutting elements is associated with a leading cutting element on
the same blade as the width of the blade increases.
51. A bit as defined in claim 44 wherein the blades increase in
width in a direction from said forward drilling face toward said
rearward connection area.
52. A bit as defined in claim 44 wherein said blades have a
variable width and an increasing number of multiple associated
cutting elements is associated with a leading cutting element on
the same blade as the width of the blade increases.
53. A bit as defined in claim 43 wherein:
a portion of each associated cutting element is buried in the blade
to secure the associated cutting element to the bit body and
wherein the associated cutting element thus secured has a cross
section, taken along a plane disposed at a right angle to said
central cutter axis, that is substantially circular, oblong,
elliptic or oval,
the leading cutting elements comprise polycrystalline diamond
compacts (PDC) cutting elements and the associated cutting elements
are comprised of a composite material containing abrasive
particles,
the blades increase in width in a direction from said forward
drilling face toward said rearward connection area,
multiple associated cutting elements are associated with each other
and a leading cutting element on the same blade and at least a
portion of each multiple associated cutting element is disposed to
trail in the groove cut by one of the cutting elements with which
it is associated, and
the number of associated cutting elements associated with a leading
cutting element on the same blade increases as the width of the
blade increases.
54. A bit as defined in claim 53 wherein the associated cutting
elements are prefabricated elements disposed in locations provided
in a mold used to form the bit body whereby the associated elements
are fixed to the bit body by liquid metal infiltration during the
fabrication of the bit body.
55. A bit as defined in claim 54 wherein the associated cutting
elements are cylindrical disk bodies comprising sintered or
infiltrated tungsten carbide containing diamond particles or
thermally stable synthetic diamond particles.
Description
The present invention concerns a drill and/or core tool in
particular for oil drilling and/or coring, comprising:
a body showing a substantially cylindrical peripheral surface and a
front, considered in a movement direction during drilling and/or
coring,
blades which extend from the front till over the peripheral surface
and which show each a leading edge for the drilling and/or
coring,
possibly Polycrystalline Diamond Compacts (PDC) cutting elements
which are situated at least in a central area of the front and the
longitudinal axes of which are transverse to the rotation axis of
the tool, and
nozzles for supplying a drilling liquid.
There is a constant need to increase the efficiency of such tools
so that their penetration speeds in the formations to be drilled or
cored are the fastest without reducing the life of the tool, i.e.
without unnecessarily increasing the weight to which it is
subjected to drive it forwards during the operation.
Research is at the same time done to increase an average
penetration rate, to increase the time during which a tool can be
kept operative in a same drill and/or core hole so as to avoid time
wasted for raising the tool up again, controlling, possibly
replacing it and for resuming the drilling and/or coring
operation.
An object of the present invention is to improve the presently
known drilling and/or coring conditions and proposes to this end a
tool which provides, on the one hand, a particularly advantageous
and economic arrangement of the blades and cutting elements to
avoid unnecessarily crushing again of fragments detached from the
formation and which provides, on the other hand, a reserve of
cutting elements which will practically only be used and acted upon
if necessary, for example in case a cutting element, possibly a PDC
element, situated on a leading edge is torn away.
To this end, said tool comprises according to the invention
moreover, on at least one blade, outside said central area,
PDC cutting elements and/or secondary cutting elements which show
each a cutting edge, forming together the leading edge of the
blade, and the longitudinal axis of which is transverse to the
rotation axis, and
at least one associated cutting element
which is situated, when considering a drilling rotation of the
tool, behind at least one of the PDC or secondary cutting
elements,
which shows a cross-section of the same shape, at least for its
portion protruding from the blade, than that of the PDC or
secondary cutting element,
which is disposed on the same blade and
an edge of which destined for cutting is situated at the most on a
same radial distance from the rotation axis and at least on a same
distance, measured parallel to this rotation axis starting from a
plane perpendicular to this axis and situated in front of the tool,
than the cutting edge of said PDC or secondary element.
According to an embodiment of the invention, the leading edge of
the blades has the shape of a helix with a possibly variable radius
and which turns, at least along said peripheral surface, either in
the direction opposite to the drilling rotation or in the same
direction as it moves away from the front.
According to a particular embodiment of the invention, the width of
a blade, taken in a projection plane perpendicular to the rotation
axis, increases as one moves away from this rotation axis over the
front, and/or from this front in the direction of a back of the
tool. It may then be advantageous that the number of cutting
elements arranged one behind the other on a same blade and on the
same of said distances, radial and parallel to the rotation axis,
increases progressively, in particular with one element having
preferably a length equal to the length of said cutting elements,
as the width of the blade increases.
Other details and particularities of the invention will become
apparent from the secondary claims and from the description of the
drawings which are annexed to the present specification and which
illustrate by way of non-limitative examples various embodiments of
the invention.
FIG. 1 shows schematically in a half plane view, as tool, a drill
bit of the invention.
FIG. 2 shows schematically, in an axial section, a superposition of
the projections of all the PDC and secondary cutting elements of
the different blades of a drill tool in the half section plane
after an adequate rotation around the rotation axis.
FIG. 3 shows schematically in a half plane view, as tool, a core
bit of the invention.
FIG. 4 shows schematically, in the same way as FIG. 2 but
simplified, the projections of the circular PDC cutting elements
and oblong secondary cutting elements of different blades.
FIG. 5 shows schematically, in a partial plane view, another
embodiment of a drill bit as tool of the invention.
FIG. 6 shows schematically, in the way of FIG. 4 but on another
scale, a projection, in a half axial plane, of the cutting elements
of the various blades of a drill bit of the invention.
In the different figures, the same reference numerals indicate
identical or analogous elements.
As shown in FIGS. 1, 2 and 3, the tool 1 of the invention comprises
in a known way a body 2 showing a substantially cylindrical
peripheral surface 3 and a front 4 when considering a drilling
and/or coring direction. Blades 5 extend from the front 4 until
over the peripheral surface 3 and show each a leading edge 6 for
the drilling and/or coring.
PDC cutting elements 7 (Poly crystalline Diamond Compact) are
situated at least in the central area 15A and are arranged to have
their longitudinal axes directed transversally to the rotation axis
of the tool 1.
PDC elements 7C can be divided along the leading edge 6 of each
blade 5; they show each a cutting edge 8 forming together the
leading edge 6.
According to FIG. 1, the elements which are divided along each
leading edge 6 and which show each on this edge a cutting edge 8,
are secondary elements 10. According to the invention, it is also
possible to conceive any mixing of secondary elements 10 and PDC
elements 7C along same leading edge 6.
By secondary cutting element 10, it can be understood here a
cutting element arranged outside the central area 15A, and the
cutting edge 8 of which is part of the leading edge 6. Such a
secondary element 10 can be made by sintering and may comprise
abrasive grits and a metallic bond.
Usually, nozzles 9 (FIGS. 1 and 2, not shown in FIG. 3) are
provided on the front 4 in order to supply an adequate liquid there
through to the bottom of the hole during the operation.
According to the invention, the tool 1 comprises moreover, behind
at least one PDC cutting element 7C (FIG. 5) or one secondary
element 10 (FIG. 1), when considering a drilling rotation S of the
tool 1, at least one cutting element 10A associated to element 7C
or 10, which has a cross-section of the same shape, at least for
its part protruding from the blade 5, than that of this latter
element and which is disposed on the same blade 5 as the element 7C
or 10 to which it is associated. Moreover, a cutting edge 11 of the
associated element 10A is situated at the most on a same radial
distance R (FIG. 2) of the rotation axis and at least on a same
distance D, measured parallel to this rotation axis starting from a
plane P perpendicular to this axis and situated in front of the
tool 1, than the cutting edge 8 of the associated PDC 7C or
secondary 10 element. The associated element or elements 10A can
thus be set back with respect to the elements 7C or 10 (FIG. 6) as
regards the formation to be drilled or cored.
In this way, if the PDC 7C or secondary 10 element wears off or is
torn away from the tool 1 or is broken, the associated element 10A,
"hidden" until then behind this element 7C or 10, may come in
action and practically no effect will be felt on the drilling
and/or coring efficiency.
FIGS. 1 and 5 show for example that beyond a certain diameter
around the rotation axis, one or more associated elements 10A are
thus situated behind each PDC 7C or secondary 10 element arranged
on the leading edge 6 of a same blade 5. It can also be seen that
the associated PDC 7 and secondary 10 elements form then each time
a portion of a ring centred on the rotation axis.
The majority of the PDC cutting elements 7 or 7C being usually
cylindrical, it may be preferred that the secondary 10 and/or
associated 10A elements are also cylindrical and show then
advantageously a diameter equal to that of the corresponding PDC
element 7C. The diameters of the PDC 7, 7C, secondary 10 and/or
associated 10A elements can either all be equal or different one
with respect to the other, for example in function of their
distance with respect to the rotation axis.
In the case of the core bit 1 of FIG. 3, the cutting elements 10
which are the closest to the rotation axis are illustrated as
having a same diameter and a same orientation around this axis as
the other cutting elements 10 situated further away from the
rotation axis. Moreover, these closest elements 10 are illustrated
as having a length greater than that of the other elements 10
situated further away from the rotation axis. However, they could
have the same length as these latter elements. Usually, the core
bit 1 does not comprise PDC cutting elements 7.
In the case of the drill bit 1 of FIG. 1, the PDC cutting elements
7B which are the closest to the rotation axis are illustrated as
being directed each transversally (mounted for example on known
intermediary studs) with respect to a corresponding axial plane.
PDC elements 7C (FIG. 5) such as those situated on diameters
greater than said determined diameter around the rotation axis, can
also be mounted in such a manner on the blades 5 that their
longitudinal axis is inclined with respect to a plane (that of the
drawing) perpendicular to the rotation axis in such a manner that
their end face comprising the cutting edge 8 is turned somewhat
towards a bottom of the hole to be drilled or towards the formation
17A to be drilled.
In the case of FIG. 2, all the PDC 7C or secondary 10 and
associated 10A cutting elements have a same diameter and, on a same
blade 5, the associated elements 10A situated at a same radial
distance R as the corresponding secondary 10 or PDC 7C element are
maximally at a same distance D, parallel to the rotation axis, as
this PDC element 7 with respect to the perpendicular plane P.
The PDC 7C, secondary 10 and associated 10A elements have been
illustrated hereinabove as being cylindrical (FIGS. 2 and 6).
However, at least certain associated elements 10A could show other
cross-sections, for example oblong, elliptic or oval (FIG. 4), the
large axis of the oval or the ellipse may then be advantageously
substantially perpendicular to a plane tangential to an envelope
15B of the cutting elements 7, 10, 10A at the place of contact
between the cutting edge 11 of the associated element 10A in
question and this envelope 15B. Oblong associated elements 10A of
this kind increase what can be called the volume of abrasive
material per active surface unit of the tool 1, given the reserve
that is accumulated thereby in the depth in the tool 1 and which
can be used. However, it appears that circular associated elements
10A increase already considerably this volume with respect to the
case of the so-called impregnated tools.
In the tool 1 of the invention, the PDC 7C (FIG. 5) or secondary 10
(FIGS. 1 and 3) cutting elements and the adjacent associated
elements 10A are preferably practically coupled to one another by
their end faces which are directed towards each other. Possible
interstices between two adjacent associated cutting elements 7C,
10, 10A, for example as a result of the curvature of the tool 1
seen in a secant plane perpendicular to the rotation axis, can be
filled in a way which is usual in the art (infiltration material,
adequate mastic, etc.).
Advantageously, the leading edge 6 of each blade 5 of the tool 1 of
the invention shows on the whole a helical shape with a diameter
which varies from the rotation axis or from its extremity the
closest thereto, over the front 4, till its opposite extremity
situated on the cylindrical peripheral surface 3 of the body 2.
This helix may turn either in the same direction or in the opposite
direction of the rotation direction S during drilling as it
diverges from the rotation axis and/or from the front 4. For
example, according to whether one wishes to evacuate the fragments
drawn out of a bottom of the hole by the cutting elements 7, 10,
10A rather quickly, the blades 5 can be made to function in a way
of an Archimedian screw or an auger bit as shown in FIG. 1.
Moreover, in a plane view, the leading edge 6 may start radially,
or close to the rotation axis even in the rotation direction S of
the tool, and may deviate subsequently to be directed in the
opposite direction of said rotation direction S.
As shown in FIGS. 1, 2, 3 and 5, each blade 5 may protrude from the
body 2 and may present, as outer surface, a portion of a revolution
surface 12 wherein PDC 7C or secondary 10 and associated 10A
cutting elements are implanted and which is delimited by anterior
13 and posterior 14 (according to the rotation direction S during
drilling or coring) lateral faces which, in projection (FIGS. 1, 3
and 5), follow the helical shape of a corresponding leading edge 6.
So, the anterior lateral face 13A of a blade 5A follows the shape
of the leading edge 6A of this same blade 5A whereas the posterior
lateral face 14A of this blade 5A follows rather the shape of the
leading edge 6B of the following blade 5B or further an
intermediary path between those of the leading edges 6A and 6B.
Advantageously, the width of the surface portion 12 and hence the
width of the blade 5, measured in a projection plane perpendicular
to the rotation axis, increases as one moves away from this latter
axis over the front 4 and/or as one moves away from this front,
over the peripheral surface 2, in the direction of a back 15 (FIG.
2) of the tool 1.
As the width of a blade 5 increases like hereinabove, the number of
associated cutting elements 10A arranged one behind the other and
behind a cutting element 7C, 10 on the blade 5, at a same level D
taken parallel to the rotation axis and with respect to a plane P
which is perpendicular thereto, may increase progressively with one
associated element 10A. It may be preferred that all the PDC 7C
and/or secondary 10 and/or associated 10A elements have the same
length. However, it may also be advantageous, for example in order
to follow the increase of the width, of the blades 5 better, that
at least certain associated elements 10A of a blade 5 have
different lengths, for example equal to half the length of the
other cutting elements 7C, 10, 10A arranged in line at a same level
D on a blade 5.
The secondary 10 and/or associated 10A cutting elements are
advantageously made of a less expensive material than that of the
PDC elements 7. The secondary 10 and/or associated 10A elements are
for example made of a composite material containing abrasive
particles. This may be sintered or infiltrated tungsten carbide,
known by the man skilled in the art, possibly comprising diamond
particles.
However, certain so-called associated elements 10A can also be made
of PDC and arranged for example between two other associated
elements 10A of a composite material which is less expensive than
PDC, in a same line and at a same level on a blade 5. Secondary 10
and/or associated 10A elements can also be made of what is called
in the art thermally stable synthetic diamond.
The secondary 10 and/or associated 10A elements may have mutually
different hardnesses, for example according to their position on
the tool 1, and may also contain variable percentages (by volume)
of abrasive and/or diamond particles.
As shown in particular in FIG. 1, at least one blade 5 may extend
until in a central area 15A of the front 4 and one of the blades 5
may have there a PDC cutting element 7B which acts practically in
the middle of this front 4. In this central area 15A, the blade or
blades 5 may preferably comprise only PDC cutting elements 7B
without associated cutting element 10A. Blade 5A may for example be
closer to the rotation axis than the other blades 5 and may have a
reduced width in this central area 15A
Other blades, such as SB may start outside the central area 15A and
may have as from their start a width such that several cutting
elements 7C or 10 and 10A can be arranged thereon in line at a
first level D the most to the front of this blade 5B.
On the front 4 spaces can be made between the different blades 5 to
arrange nozzles 9 therein. Drilling (FIG. 1) and/or coring liquid
ducts can be provided in the usual way in the tool 1. The outlet
nozzles 9 for this liquid may be of a type to be screwed in the
tool 1 so as to be exchangeable in function of their outlet
dimensions and hence of the liquid flow rate towards the bottom of
a hole which is being drilled.
However, the nozzles 9 can be formed by prefabricated elements.
During the manufacturing of a tool 1 by moulding, these
prefabricated elements can then be placed in locations provided in
the mould at the same time as PDC 7, secondary 10 and associated
10A cutting elements are placed therein in adequate locations. The
mould is then filled in a usual way with solid elements and powdery
materials which form in a way known per se, after infiltration with
a liquid metal in this mass, the body 2 and the actual blades 5,
the liquid metal fixing thus at the same time the prefabricated
elements and the cutting elements 7, 10, 10A to the blades 5
produced in this way.
Of course, from one blade 5 to the other, the cutting elements 7,
10, 10A are arranged at levels D and distances R from the rotation
axis chosen so that in a projection in a plane passing through the
rotation axis (FIGS. 2, 4 and 6), the cutting elements 7, 10, 10A
are complementary to one another to form on the bottom of a drilled
or cored hole an envelope 15B of leading edges 6 which is as
regular as possible, without leaving high circular projections 16
between two circular grooves 17 drawn by the cutting edges 8, 11 of
the whole of the leading edges 6 in the formation 17A to be drilled
or cored.
It has to be understood that the invention is in no way limited to
the described embodiments and that many modifications can be
applied thereto without departing from the scope of the present
invention.
In this way, the front 4 of the drill tool 1 (FIG. 2) is preferably
concave in the central area 15A and the cutting elements 7, 10, 10A
are disposed therein to cut a drill hole bottom which is
substantially conical with a low gradient, for example between
10.degree. and 30.degree. with respect to a plane perpendicular to
the rotation axis, the cone pointing towards the back 15 of the
tool 1 in the working position. A gradient of 20.degree. may be
preferred.
Moreover, the helical blades 5 are advantageously arranged on the
peripheral surface 3 in such a manner that, seen according to the
projection of FIG. 1, a blade 5A covers the posterior extremity 18F
of a blade 5F which extends (in the case of this figure) according
to arrow 19A until below the part of blade 5A which is visible in
this view, and the same for the others. So, there is assured an
uninterrupted rolling, without chocks (and hence improved), of the
tool 1 against a wall, for example of the hole which is being
drilled.
In the projection of FIG. 1, the helix described in the case of the
drill tool 1 can be considered as being, on the front 4, a part of
a spiral followed, on the peripheral surface 3, by an actual
helix.
Each time between two blades 5 a channel 19 (FIGS. 1 and 2) is
provided which becomes advantageously wider at least as from its
extremity which is the closest to the rotation axis and possibly
until a predetermined width is achieved, for example to the extent
that the blades 5 which border it become larger.
The secondary 10 and/or associated 10A cutting elements have
preferably their (anterior and/or posterior) end faces 20 parallel
to the rotation axis of the tool 1. These end faces 20 may form an
angle with a radius starting from this rotation axis and going
through any of their points.
How to implement the invention to a core bit will be understood
after having read the preceding part and after having examined the
corresponding FIG. 3 wherein possible coring liquid nozzles have
not been shown. One will notice in particular a shift in radial
distance between the first cutting element 10 of a blade 5 and the
one of the following blade, and thus of the following cutting
elements 10, 10A on each blade 5. The elements which are the
closest to the rotation axis can be arranged with their
longitudinal axis perpendicular to the rotation axis, as shown, or
may show a particular inclination so that the cutting edge 8 forms
a predetermined cutting angle with the formation 17A to be
drilled.
LIST OF REFERENCES
1. Tool
2. Body
3. Peripheral surface of 2
4. Front of 2
5. Blade (of which in particular the blades 5A, 5B, 5F are
indicated)
6. Leading edge of 5 (of which in particular the edges 6A, 6B of
the corresponding blades are indicated)
7. PDC cutting element (of which also variants 7B and 7C are
indicated in function of their relative positions)
8. Cutting edge of 7, 10
9. Nozzle
10. Secondary cutting element
10A. Associated cutting element
11. Cutting edge of 10A
12. Revolution surface portion of 5
13. Anterior lateral face of 5 (of which in particular 13A of the
corresponding blade 5A is indicated)
14. Posterior lateral face of 5 (of which in particular 14A of the
corresponding blade 5A is indicated)
15. Back of 1
15A Central area of 4
15B. Envelope
16. Projections
17. Grooves
17A. Formation
18. Posterior extremity of 5 (of which in particular 18F of the
corresponding blade 5F is indicated)
19. Channel
19A. Arrow
20. End faces of 10, 10A
P Perpendicular plane in front of the tool 1
D Distance from P
R Radial distance
S Rotation direction of the tool 1.
* * * * *